Hillary Clinton

STEVE MARCUS / LAS VEGAS SUNSen. Hillary Clinton, D-NY, visits with members of the Culinary Workers Union, Local 226 at the union headquarters on May 30, 2007.

Party:DemocraticPolitical position:U.S. Senator from New York (2000-present)
Age: 60Clinton’s Credentials:The former first lady and New York Senator has built her campaign around four themes: Restoring America's reputation around the world, restoring the American middle class, reforming the government and reclaiming the future for today's children.

What was once a liability for Clinton is now a strength. Her failure to achieve health care reform in 1993 and 1994 was initially seen as her biggest setback and a major catalyst to the Republicans' 1994 mid-term electoral victory, but now Clinton is viewed by Democratic voters, according to polls, as the most trustworthy and likely to get major reform passed, even though she was the last of the three major candidates to make a formal proposal.

She's run a disciplined campaign that has racked up big fund-raising totals and political endorsements here and everywhere else. She had even begun pivoting away from the Democratic primary and toward the general election campaign until a recent debate in Philadelphia, where the other candidates questioned her candor, bursting the inevitability bubble that had surrounded her campaign from the start.

Despite her strengths in organization, preparation and raising funds, Clinton has vulnerabilities as a candidate. Clinton voted to authorize President Bush to use force in Iraq, which will never be forgiven by many of the party's most devout voters, the very people who turn out in early primaries and caucuses. Unlike John Edwards, another top Democratic contender, Clinton has declined to apologize for the vote.

Another challenge: Although Clinton has proved to be an effective campaigner, especially in the town hall format, much of the country has fixed opinions about her, formed over 15 years. Moving the favorability meter even a bit will take considerable effort and skill, but her husband, former President Bill Clinton, enjoys high approval ratings from independents, who are trending Democratic this election cycle, which could help should she win the nomination.